Gibberellic Acid-Induced Synthesis of Protease by Isolated Aleurone Layers of Barley

Jacobsen, John V.; Varner, Joseph E.

doi:10.1104/pp.42.11.1596

Cited by 305 publications

(125 citation statements)

References 13 publications

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“…The embryo secretes gibberellin (13,34,44), and it has been shown that exogeneously applied gibberellic acid causes considerable ultrastructural changes in aleurone cells (32,33). This discovery led to a large number of investigations concerning the mode of action of gibberellic acid on isolated aleurone layers, and the capability of aleurone cells to produce enzymes necessary for the degradation of the endosperm in the seed is now well established (5,15,17,19,20,21,23,39,40). Other studies have, however, shown that also the scutellum secretes enzymes (2,3,4,6,11,12,24,31).…”

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confidence: 99%

The ultrastructure of germinating barley seeds. I. Changes in the scutellum and the aleurone layer in Nordal barley

Gram

1982

Carlsberg Res. Commun.

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The ultr~tstructure of the scutellum and the aleurone layer has been examined in seeds of Nordal barley following malting for 0, 30, 72, 120 and 162 hours at 15 ~ Thick sections from the seeds were stained with Calcofluor White M2R New and examined in the light microscope to determine the extent of cell wall degradation in the endosperm.The changes in the scutellar parenchyma cells include degradation of the protein bodies and the appearance of vacuoles and prominent amyloplasts. The analysis of a serially sectioned epithelial cell from the scutellum 72 hours after the start of malting revealed a large number of Golgi apparatuses, preferentially located near the cell wall. It is suggew that the presence and location of the Golgi apparatuses are related to enzyme secretion. Following malting for 72 hours or more, the epithelial cells contain lomasomes and membrane aggregates, termed membrane bodies. The analysis indicated that lomasomes originate from the membrane bodies and are involved in the growth of the cell walls of the epithelium. Organelles indicating cellular activity, i.e., rough endoplasmic reticulum, mitochondria and Golgi apparatuses, first appear in the epithelial cells of the scutellum, and later in the cells of the aleurone layer. Furthermore, the degradation of the endosperm starts in the vicinity of the scutellum as judged by the ca|cofiuor staining. Therefore, it is concluded that the scuteltar epithelium provides the enzymes during the initial degradation of the endosperm. In seeds malted for 162 hours, aleurone ceils with a cytoplasmic organisation indicative of active metabolism are located in the embryo part of the seed, whereas aleurone ceils adjacent to unmodified endosperm in the distal end of the same seed show little or no structural sign of activity.

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Section: Introductionmentioning

confidence: 99%

The ultrastructure of germinating barley seeds. I. Changes in the scutellum and the aleurone layer in Nordal barley

Gram

1982

Carlsberg Res. Commun.

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“…Enhanced protein biosynthesis is observed well before root protrusion has taken place; therefore, it could be an early preparative step toward germination. In isolated aleurone layers of barley and wild oat, gibberellins stimulate synthesis of amylases (12,15,14,11) and protease (9). It has been stated that gibberellic acid promotes seed germination by enhancement of hydrolase synthesis (1,8).…”

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Respiration and Protein Synthesis in Dormant and After-ripened Seeds of Avena fatua

Chen

Varner

1970

Plant Physiol.

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Measurement of Oxygen Uptake. The uptake of 02 was measured by means of a Gilson differential respirometer. Sterile precautions were taken as described previously (4). Each flask contained 10 seeds. Two flasks were included in each treatment.Incorporation of 1'C-Leucine into Protein. Lots of 10 seeds were husked, pricked at the dorsal side of the endosperm (a measure which facilitates entry of the applied compounds without affecting germination), sterilized in 1 % NaOCI for 2 min, washed, placed in a 25-mi Erlenmeyer flask with 2 ml of water, shaken at 21 -:-1 C for a period of time, then transferred to 1 ml of 1 mM leucine with 2.5 ,uc of uniformly labeled '4C-leucine (specific radioactivity 290 mc/mmole, New England Nuclear Corp.), and further shaken for 2 hr. The seeds were then washed in ice-cold, nonradioactive leucine solution, homogenized, extracted in 4 ml of 0.2 M NaCl plus 0.1 mm leucine, and centrifuged at 12,000g for 15 min. The pellet was suspended in 4 ml of the salt solution and recentrifuged. One twentieth of the pooled 12,000g supernatant fraction was precipitated with an equal volume of 15% trichloroacetic acid, and the precipitate (soluble protein) was collected on a Millipore filter. The filter was dried and the radioactivity was determined in a Nuclear Chicago gas flow detector with a counting efficiency of 40% for carbon-14. The pellet was suspended in water and precipitated in the same way as above. Approximately 80% of the radioactivity associated with the acid-insoluble material could be released by pronase, a potent proteolytic enzyme of bacterial source. Thus, this material is considered as insoluble protein.Microautoradiography of Seeds Exposed to 3H-Leucine. To locate the sites of protein synthesis, the seeds were exposed to L-leucine-4, 5-3H (specific radioactivity 6.0 c/mmole, Schwarz BioResearch), then washed in nonradioactive leucine, fixed, dehydrated and infiltrated with paraffin according to the technique of Feder and O'Brien (7). Sections 5 to 8 ,u thick were placed on a slide, dewaxed, coated with Kodak nuclear track emulsion type NTB 3, exposed, stained with toluidine blue-acid fuchsin, mounted, and examined under the microscope (10). RESULTSRespiratory Intensity. The rate of respiration (02 uptake) in dormant seeds was low as compared to that of nondormant seeds; the difference could be detected from the early hours of soaking (Fig. 1). In both kinds of seeds, the rate increased with time. However

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“…The (8) for the GA-induced synthesis of amylase and proteinase production in barley half seeds. In barley GA added to isolated aleurone layers evokes cytological changes during the lag period similar to those that take place during normal germination; that is, vacuolation, breakdown of aleurone granules and an increase in the number of polysomes, mitochondria, and microbodies (17).…”

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Assay and Biochemical Properties of the Proteinase Inhibitor-inducing Factor, a Wound Hormone

Ryan¹

1974

Plant Physiol.

115

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MATERIALS AND METHODSAn assay has been developed for the proteinase inhibitor-inducing factor (PIIF), a wound hormone. PIIF is present in tomato (Lycopersicum esculentum var. Bonnie Best) leaf extracts and induces accumulation of proteinase Inhibitor I when the extracts are supplied briefly to excised leaves that are subsequently incubated in water under constant light. An active water-soluble crude PIIF solutioit was cosiveniently prepared from autoclaved and lyophilized tomato leaves. Accumulation of Inhibitor I, induced by crude PIIF, is linear, commencing at about 8 to 10 hours after feeding and continues for several hours. Evidence is presented that the PIIF-induced accumulation of Inhibitor I, determined immunologically, is accompanied by the accumulation of other trypsin and chymotrypsin inhibitors, determined enzymatically. (30-10-10), and 0.001% ferric iron. Unless otherwise mentioned, plants were used for assay when they were about 7.5 to 10 cm in height and having two well formed leaves and a third, smaller apical leaf. The assay for PIIF in excised leaves, described herein, requires that the young plants be grown pest-free and with optimal additions of fertilizers. We have found that leaves from plants supplied with low levels of nitrogen or iron do not respond well to PIIF, nor do plants grown under subdued light. On the other hand, if healthy young plants are transplanted after the root systems have become well established the roots tear and apparently release PIIF, resulting in high levels of inhibitors in the leaves. Inhibitor I was assayed immunologically by the method of Ryan (10). Purified Inhibitor 1 (9) from potatoes was used as a standard. Tomato and potato Inhibitor I are immunologically very similar (4), but the quantitation is relative to the potato Inhibitor I, since the tomato Inhibitor I has not been fully purified.Enzymatic determination of total chymotrypsin and trypsin inhibitors in tomato leaves was performed by the method of Hummel (7)

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Gibberellic Acid-Induced Synthesis of Protease by Isolated Aleurone Layers of Barley

Cited by 305 publications

References 13 publications

The ultrastructure of germinating barley seeds. I. Changes in the scutellum and the aleurone layer in Nordal barley

The ultrastructure of germinating barley seeds. I. Changes in the scutellum and the aleurone layer in Nordal barley

Respiration and Protein Synthesis in Dormant and After-ripened Seeds of Avena fatua

Assay and Biochemical Properties of the Proteinase Inhibitor-inducing Factor, a Wound Hormone

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